Safeguard device for automotive electrical systems



N. L. STARCK Se t. 15, 1959 SAFEGUARD DEVICE FOR AUTOMOTIVE ELECTRICALSYSTEMS Original Filed Dec. 4. 1953 NOEL L. STARCK,

mmvroa. W A7 TORNEG.

United States Patent 2,904,102 SAFEGUARD IFQR AUTOMGTIVE EL CT-RiserSYSTEMS Noel L. :Starck, Los Angeies, Calife 'flriginal applicationDecember 4, 1953, Serial No.

$596, 9.; Diyided and this application September 17,

1956, Serial No. 610,069

This invention relates to an electrical circuit for an internalcombustion engine and is directed .to ,a circuit incorporatingasafeguard against short circuits and against any heavy current flowwhatsoever when the engine is not in operation. The present disclosureis directed by way of example to such a safeguard for an automotivevehicle.

The present application is a division of copending application, Ser. No.396, 39, which was filed December 4, 1 953, and entitled SafeguardDevice for Automotive Electrical Systems, and which has now becomeabandoned.

One advantage of such an arrangement is, of course, the elimination offire hazard, and especially when the vehicle is parked and unattended. Asecond advantage is the prevention of damage to the components -of thewiring system that may arise from short circuiting or overloading. Athird advantage is conservation of the battery itself as well assafeguard against running down the battery.

A fourth advantage .is that the invention discourages car theftespecially when the invention is installed on an automobile having alocked hood. A .car thief cannot use a jumper wire to shunt the ignitionkey at the dash because all of the circuitry at the dash isale-energized. Such a jumper wire can be installed successfully only ifaccess is gained to the present invention which is installed under thehood of the car.

In general these advantages are provided by an electrical automotivecircuit in which at least one side of the battery is completely isolatedor disconnected when the ignition switch is open and in which currentflow through the circuit under direct control of the -ignition switch isheld toaminimum. Thus, when the key for the ignition switch iswithdrawn, no circuits whatsoever can beclosed through the storagebattery of the vehicleand when the ignition key is inserted to close theignition switch, the result is merely relatively light current flowthrough a limited portion of the wiring system.

A feature of the preferred practice of the invention is the use of ,abattery-isolated relay having two coils to provide two differentmagnitudes of contact-closing force. One of these two coils of the relayis a main coil that is employed for normal energization of theelectrical system by the storage battery. The other of the two coils isanauxili-ary coil or supplemental coil which may be aptly termed abooster coil since it provides added contactclosing force. The solefunction of the ignition switch .of the automotive wiring circuit is toenergize the main coil fora minimum level of current flow from thebattery, the current being sufficient to close the relay with relativelylight contact-to-cont-act pressure. Since the contacts of this relay inthe one practice of the invention provide the only connection betweenone side of the battow and the rest of the wiring system, the contactsmust, on occasion, carry peak load imposed on the storage battery by theengine starter. The starter switch is connected to the relay contactsand provision is made for energizing the second or booster coil of therelay in response to energization of the engine starter. Thus, thestarter circuit cannot be closed unless the ignition switch is firstclosed and the booster coil is automatically energized to increase thecontact-toecontact pressure of the relay whenever the demand arises forpeak current flow 2,904,702 Patented .Sept. 15, 1 959 through the enginestarter circuit. In this way, one circuit arrangement of the presentinvention makes it .possible to use a minimum level of current flow 1toconnect the battery with the rest of the circuit and to hold the batteryconnection closed during normaloperation of the engine. At the same timethe circuit arrangement provides for additional flow of current toenergize the relay when required to prevent overheating, burning andpitting of the relay contacts.

One practice of the invention .is further characterized by theprovision, as a new article of manufacture, of :a simple unit that maybe added to any automotive electrical system to convert the wiringsystem of the vehicle to the new mode of safety operation. A feature ofthe invention in this regard is that the accessory unit may be installedin a simple manner requiring no special technical skill or knowledge.

The various features and advantages .of the invention will be apparentin the following detailed description considered with the accompanyingdrawing.

In the drawing, which is to be regarded. as merely illustrative:

Figure '1 is a schematic wiring diagram embodying .one form of theinvention;

Figure 2 is a similar diagram of a second form of the invention; and

Figure 3 is a similar diagram of a third form of the invention.

Figure 1 shows some of the essential components of a conventionalautomotive electrical system including a storage battery 10, an ignitionswitch 11, an engine starter indicated by the broken line rectangle 12,a starter switch 13 and an ammeter 14.

The engine starter 12 includes the usual starter relay, represented bythe inner solid line rectangle 18, which is of conventionalconstruction. The starter relay 18 has the usual armature 1'9 controlledby a relay coil 20 and the armature carries the usual movable contact 21which is adapted to bridge or interconnect a pair of stationary contacts22 and Normally, the movable contact 21 is held in open position by asuitable spring 24; whenever the relay coil 20 is energized, however,the armature 19 is attracted by the coil to move the contact 21 intoclosed position bridging the two stationary contacts 22 and 23. One sideof the relay coil 20 is grounded as indicated in 25 and the other sideis connected by a wire 26 to one side of the starter switch 13.

The positive side of the battery 10 is connected by a wire 30 with thestationary contact 23 of the starter relay 18 and this stationarycontact is connected by a wire 31 to one side of the ammeter 14. Thesame side of the ammeter 14 is connected by a wire 32 to the second sideof the starter switch 13 and is connected by a wire 33 with one side ofthe ignition switch 11. The other side of the ammeter 14 has at leastone wire 34 connected thereto in the usual manner to serve as anaccessory power supply conductor for energizing various componentsincluding the components of the lighting system of the automobile. Amongthe components energized by the power supply conduct-or 34 are the sparkplugs of the engine. The ignition circuit which energizes said sparkplugs is con nected directly to wire 34, and therefore its effectiveenergization is controlled by the contacts 43, 44, 45, which are closedby the energization of the main relay coil 44) (Figures 1 and 2) or ofthe relay coil (Figure 3) by the ignition switch 11, as will behereinafter more fully described.

All of the above described components are conventional in an automotiveelectrical system and, of course, a typical automotive wiring circuitincludes additional components which need not be described for thepurpose of the present disclosure.

While the principles of the invention may be incorporated in anautomotive wiring system in various ways in various practices of theinvention, preferably the necessary components for converting aconventional wiring system into the new safety system are provided by asingle unit having a housing or casing represented by the solid linerectangle 37. As will be apparent such a unit may be manufactured andsold as an accessory device to be installed in a conventional automotivewiring system.

The housing 37 of the new unit encloses a main relay coil 40, anauxiliary booster relay coil 41 and a relay armature 42 that is commonto and responsive to both of these coils. The armature 42 carries amovable contact 43 to bridge or interconnect a pair of stationarycontacts 44 and 45. A suitable spring 46 urges the movable contact 43 tothe open position shown in Figure 1 and en ergization of either of thetwo coils 40 and 41 moves the contact 43 to closed position inopposition to the spring 46.

The stationary contact 44 is integral with a terminal 47 on the exteriorof the unit casing 37 for connection with the negative side of thebattery by a wire 48. In like manner, the stationary contact 45 insidethe unit is integral with an exterior terminal 49 for connection by awire 50 to ground as indicated in the drawing.

One end of the main relay coil 40 of the unit is connected to thestationary contact 44, preferably through a suitable resistor 54 thatlimits the amount of current flow through the coil but neverthelesspermits suflicient current flow to overcome the resistance of the spring46. The other side of the main relay coil 40 is connected to an externalterminal 55 of the unit for connection by a wire 56 to the second sideof the ignition switch 11. One side of the booster relay coil 41 isconnected to the stationary contact 45 and the other side is connectedto an external terminal 57 of the unit for connection by a wire 58 withthe stationary contact 22 of the starter relay 18. This stationarycontact 22 of the starter relay is connected in the usual manner to thestarter motor by a wire 59, the other side of the starter motor beinggrounded to complete the starter circuit.

When the ignition switch 11 is closed, the following circuit iscompleted to energize the main relay coil 40; the positive side of thebattery 10; wire 30; wire 31; wire 33: ignition switch 11; wide 56:terminal 55 of the safety unit: coil 40; resistor 54; terminal 47 on theexterior of the unit: and wire 48 to the negative side of the battery.

Energization of the main relay coil 40 by closing of the ignition switch11 actuates the armature 42 to make it possible for the starter switch13 to energize the starter relay 18. When the starter switch 13 is thenclosed while the ignition switch 11 is closed, the following circuit iscompleted through the coil of the starter relay 18: the positive side ofthe battery 10; wire 30; wire 31; wire 32: starter switch 13; wire 26;starter relay coil 20; ground wire 50 from ground to the externalterminal 49 of the unit; contact 45 inside the unit; movable contact 43;contact 44; external terminal 47; and wire 48 to the negative side ofthe battery.

The closing of the movable contact 21 against the two stationarycontacts 22 and 23 resulting from energization of the coil 20 of thestarter relay 18 completes the following circuit for energization of thebooster relay coil 41 in the unit casing 37: positive side of thebattery 10; wire stationary contact 23 in the starter relay 18; movablecontact 21; stationary contact 22; wire 58; terminal 57 of the unit;booster relay coil 41; contact 45; movable contact 43; contact 44;external terminal 47; and wire 48 to the negative side of the battery.

From the foregoing, it is apparent that when the ignition switch 11 isopen, the negative side of the battery 10 is isolated or disconnected toprevent any current flow whatsoever throughout the wiring system, andthat when the ignition switch 11 is closed, only such relatively weakcurrent will flow as will be necessary to energize the main relay coilfor holding the movable contact 43 lightly against the two stationarycontacts 44 and inside the unit. It is further apparent that when thestarter switch 13 is closed to draw a peak load of current from thebattery 10 for energizing the engine starter, the booster relay coil 41will be automatically energized at the same time to increase thepressure of the movable contact 43 against the two stationary contacts44 and 45 for more effective cooperation of the contacts to avoidoverheating, burning and pitting of the contact surfaces.

It will be readily appreciated that it is a simple matter to install thenew unit in a conventional automotive wiring system. In this instance,prior to installation of the unit, the negative side of the battery 10is grounded and it is merely necessary to interpose the unit between thebattery and ground. Thus, the unit casing 37 is mounted in a convenientlocation for connection of the unit terminal 47 to the battery and theunit terminal 49 to ground. The other wires of the system are rearrangedfor the proper connection with the two unit terminals and 57, theignition switch being connected to one terminal and the starter switchbeing connected to the other.

The Wiring diagram of the second embodiment of the invention shown inFigure 2 is largely identical with the wiring diagram shown in Figure 1,as indicated by the use of corresponding numerals to designate identicalparts. In this instance, the unit, which has a casing 61, is installedin an automotive wiring system in which the storage battery has itspositive side grounded as indicated at 63, and the external terminal 47of the unit is connected to the negative side of the battery by the wire48. The particular embodiment of the unit employed in this arrangementhas a fifth external terminal 64 which is grounded as indicated at 65and the booster relay coil 41 is connected to this terminal as shown. Inall other respects the unit of Figure 2 is the same as shown inFigure 1. p

The terminal 55 of the unit is connected by the wire 56 to one side ofthe ignition switch 11, as before, but the second side of the ignitionswitch is connected to ground by a wire 66. The terminal 49 of the unitis connected by a wire 69 with the ammeter 14 and is connected by a wirewith the fixed contact 23 of the starter relay 18.

When the ignition switch 11 in Figure 2 is closed, it completes thefollowing circuit to energize the main relay coil 40 of the unit:positive side of the battery 60, wire 63 to ground; ground to switch 11through wire 66; wire 56; terminal 55 of the unit; coil 40; resistor 54;stationary contact 44; terminal 47; and wire 48 to the negative side ofthe battery. The resulting energization of the main coil 40 closes themovable contact 43 against the two stationary contacts of the unit andwhen the starter switch 13 is then closed, the following circuit iscompleted to energize the relay coil 20 in the starter relay 18;positive side of the battery 60 to ground through the wire 63; ground tothe relay coil 20 of the starter; wire 26; starter switch 13; wire 32;wire 69; terminal 49; stationary contact 45; movable contact 43;stationary contact 44; terminal 47; and wire 48 to the negative side ofthe battery. The consequent closing of the starter relay 18 completesthe following circuit for energizing the booster relay coil 41 in theunit: positive side of the battery 60 to ground through wire 63; groundto terminal 64 of the unit; booster relay coil 41; terminal 57; wire 58;stationary terminal 22 of the starter relay; movable contact 21;stationary contact 23; wire 7%); terminal 49; stationary contact 45;movable contact 43; stationary contact 44; terminal 47 and wire 48 tothe negative side of the battery.

It is apparent in this second wiring arrangement the second form of theunit will operate in substantially the same manner and with the samesequence of steps as heretofore described.

The third form of the invention shown in Figure 3 is incorporated in awiring system which has a battery 70 which is grounded on its negativeside by a wire 71 and on its positive side is connected by a wire 72with the external terminal 47 of the unit. Thus, the unit is interposedbetween the positive side of the battery and the rest of components ofthe automotive Wiring system. The unit indicated in Figure 3 has asuitable casing 73 which is provided with an external terminal 74connected to ground by a Wire 75. In this instance, the unit has onlyone relay coil 80, one side of which is connected to the terminal 74 andthe other side of which is connected through a resistor 81 to theexternal terminal 55 of the unit. In all other respects the arrangementshown in Figure 3 is similar to the previously described arrangements asindicated by the use of corresponding numerals to designate identicalparts.

The unit terminal 55 is connected to one side of the ignition switch 11by the usual wire 56 and the other side of the ignition switch isconnected by a wire 82 to the fixed contact 23 of the starter relay 18.The external terminal 49 of the unit is connected to the ammeter 14 by awire 76. A wire 77 connects the previously mentioned wire 72 on thepositive side of the battery with the fixed terminal 23 of the starterrelay 18.

When the ignition switch 11 is closed in the arrangement shown in Figure3, the following circuit is completed for energization of the relay coil80 in the unit: positive side of the battery 70; Wire 72; wire 77; wire82; ignition switch 11; wire 56; terminal 55; resistor 81; relay coil80; terminal 74; wire 75 to ground; and wire 71 from ground to thenegative side of the battery. With the relay coil 80 energized, closingthe starter switch 13 completes the following circuit for energizing thecoil 20 in the starter relay 18: positive side of battery 70; wire 72;terminal 47 of the unit; stationary contact 44; movable contact 43;stationary contact 45; terminal 49; wire 76; wire 32; starter switch 13;wire 26; relay coil 20; to ground; and wire 71 from ground to thenegative side of the battery.

In this arrangement, the .positive side of the battery 70 is effectivelyisolated from the remaining components of the wiring system as long asthe ignition switch 11 is open. When the ignition switch is closed,current flows at a minor rate through the relay coil 80 to hold themovable contact 43 in closed position against the resistance of thespring 46. The peak load of current flows only when the starter switch13 is closed but a feature of this arrangement is that it is notnecessary to provide a booster relay coil in the unit for increasing thepressure of the movable contact 43 against the two stationary contacts44 and 45 because the heavy current is by-passed around the unit by thewire 77.

My description in specific detail of selected specific embodiments ofthe invention will suggest to those skilled in the art various changes,substitutions and other departures Within the spirit and scope of theappended claims.

I claim:

1. In an electrical system for an internal combustion engine and whichsystem includes a source of electrical energy, an electrical startermotor, an ignition switch and a starter switch; the combination of: astarter relay having an energizing coil providing a relatively highcurrent drain on the source and further having a pair of normally opencontacts; a second relay having a pair of normally open contacts andfurther having an energizing coil providing a relatively low currentdrain on the source; means for connecting said normally open contacts ofsaid second relay in series with the source of electrical energy, thestarter switch and said energizing coil of said starter relay tocondition said starter relay for energization by the sta ter s t 9838.for

connecting said energizing coil of said second relay in series with thesource of electrical energy and the ignition switch; and a connectionby-passing said contacts of said second relay for connecting saidcontacts of said starter relay in series with the starter motor and thesource to energize the starter motor upon energization of said starterrelay.

2. An electrical system for an internal combustion engine including: anignition switch; an ignition relay having an energizing coil connectedin series with said ignition switch across a source of electrical energyand further having a pair of normally open contacts; a starter switch; astarter relay having an energizing coil connected in series with saidstarter switch and with said normally open ignition relay and contactsacross said source and further having a pair of normally open contacts;and electrical starter means connected in series with said normally opencontacts of said starter relay and said source in a circuit bypassingsaid ignition relay contacts.

3. An electrical system for the starter motor of an internal combustionengine including: an ignition switch; an ignition relay having anenergizing coil connected in series with said ignition switch across asource of electrical energy and further having a pair of normally opencontacts; a starter switch; a starter relay having an energizing coilconnected in series with said starter switch and with said normally openignition relay contacts across said source and further having a pair ofnormally open contacts; and means by-passing said ignition relaycontacts for connecting the starter motor and said normally opencontacts of said starter relay in series across said source.

4. In combination for use with a starter motor in an internal combustionengine, a first relay winding, a second relay winding, a source ofvoltage, an ignition switch normally open to prevent the first relaywinding from being energized and manually closable to establish a firstcontinuous circuit through the voltage source to the first relay windingfor obtaining a low flow of current to energize the first relay winding,a first control switch magnetically coupled to the first relay windingfor closure upon an energizing of the winding, a starter switch normallyopen to prevent the second relay winding from being energized andmanually closable to establish a second continuous circuit to the secondrelay winding through the voltage source and the first control switch inthe closed position of the control switch for obtaining a large How ofcurrent to energize the second relay winding, and a second controlswitch magnetically coupled to the second relay winding for closure uponan energizing of the second relay winding and electrically connected ina circuit with the voltage source and the starter motor to obtain anenergizing of the starter motor upon closure; the second control switch,the starter motor and the voltage source being connected in a circuitby-passing the first control switch upon the closure of the secondcontrol switch.

References Cited in the file of this patent UNITED STATES PATENTS1,246,056 Conrad Nov. 13, 1917 1,719,539 Fought et al. July 2, 19292,202,043 Cole May 28, 1940 2,283,231 Schmitt May 19, 1942 2,304,608Smythe Dec. 8, 1942 2,481,176 Taylor et al. Sept. 6, 1949 2,485,727Gallina Oct. 25, 1949 2,492,077 Wall Dec. 20, 1949 2,500,182 HnertasMar. 14, 1950 2,515,044 Kappel July 11, 1950 2,529,195 Stone Nov. 7,1950 2,538,581 Minch et al. Jan. 16, 1951 2,591,618 Schaelfer Apr. 1,1952 2,606,626 Meyer Aug. 12, 1952

